Highly loaded clopyralid dual-salt formulation

ABSTRACT

The present disclosure provides a clopyralid formulation for dealing with weeds in crops or pastures or fallow areas. The formulation is highly loaded, clopyralid being present at a concentration of at least 600 g acid equivalent (ae) per litre. Clopyralid is present in the form of at least two amine salts, one being the monoisopropylamine salt.

TECHNICAL FIELD

The invention relates to novel clopyralid formulations. In particular, the invention is concerned with highly loaded clopyralid formulations, containing two or more salts of clopyralid.

BACKGROUND ART

Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide suitable for the control of weeds. It has been marketed globally as both solo formulations and as co-formulations with a range of other active ingredients. These formulations are used for control of weeds in a range of agricultural, commercial, home garden and industrial situations.

As a solo formulation, clopyralid liquid formulations are typically soluble liquid (SL) formulations that contain an active ingredient concentration of a single amine salt, such as dimethylammonium (DMA), potassium or triisopropanolamine (TIPA), at a concentration of 300-750 g/L or a mixture of dimethylamine (DM) and monoethylamine salts at 750 g/L. Other SL mixture formulations contain a single amine salt being the monoethanolamine (MEA), triethylamine or triethanolamine.

Existing clopyralid single-salt formulations at the >350-450 g ae/L concentration (600 g/L in commercialized formulations in Australia) have a viscosity specification that is either very low or moderate to high. The DM+monoethylamine clopyralid 750 g/L formulation currently available in Australia has a viscosity of ≈50 cP at 5° C. A low viscosity formulation may be more prone to splashing and poor containment due to spillage. A higher viscosity formulation is by definition more difficult to pour and pump under cold conditions, which are common where clopyralid formulations are used i.e. winter cereal production in Australia. An example of a low viscosity single-salt formulation is the 600 g/L MEA salt, which has a viscosity of <50 cP. An example of a high viscosity single-salt formulation is the 600 g/L TIPA salt, which has a viscosity of up to 800 cP.

High concentration formulations are generally desirable: a highly loaded formulation can deliver the required quantity of active ingredient to a user in a smaller volume and lower weight. For formulators, higher concentration formulations reduce the quantity of formulated product to be produced. There is a saving in packaging, freight costs, storage volume and energy costs and a reduction of waste.

It would be beneficial to provide formulations of clopyralid which are highly loaded to a concentration of 600 g ae/L or more and which have acceptable viscosity at temperatures commonly encountered at application times.

It has been discovered that it is possible to provide clopyralid formulations that are highly loaded yet stable, and which have acceptable viscosity, where clopyralid is present in the form of at least two amine salts, one of which is the monoisopropylamine (MIPA) salt.

SUMMARY OF THE INVENTION

Accordingly, the invention provides a clopyralid formulation containing clopyralid at a concentration of at least 600 g ae/L, clopyralid present in the form of at least two amine salts, one of which is the monoisopropylamine salt.

It has been found that clopyralid as the MIPA salt has the advantage of neutralizing the clopyralid acid to create a stable formulation.

Preferably, the second amine salt of clopyralid is the monoethanolamine salt (MEA).

The use of MEA and MIPA as neutralizing agents can also increase the compatibility of clopyralid with other salt-based aqueous concentrates, such as glyphosate and 2,4-D amine. Both MEA and MIPA are acid neutralization agents used in widely used commercial formulations of glyphosate, which can simplify the procurement of raw materials for production of multiple SL formulations.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Example 1: Soluble Liquid Clopyralid Formulation (SL) as MIPA and MEA Salts

The components were as set out in Table 1:

TABLE 1 Components Content Purpose in g/L Component Formulation Supplier 628.93 Clopyralid active Lier Chemical Co., Technical 95.4% ingredient Ltd 138.51 MIPA 70 reactant Redox Pty Ltd (Isopropylamine 70% Solution) 100.21 MEA reactant Sigma Aldrich (Monoethanolamine 98%) 75.00 TERWET ® 1255 wetting Huntsman Australia agent Pty Ltd 0.50 Rhodoline 5338 AG antifoam Solvay Interox Pty Ltd 312.74 Water diluent Potable water

Details of the components are set out in Table 2:

TABLE 2 Component Details Trade Name IUPAC NAME CAS# Clopyralid Technical 95% 3,6-dichloropyridine-2- 1702-17-6 carboxylic acid MIPA 70 (Isopropylamine 70% propan-2-amine 75-31-0 Solution) MEA (Monoethanolamine 98%) 2-aminoethanol 141-43-5 TERWET ® 1255 amines, tallow alkyl, 61791-26-2 ethoxylated Rhodoline 5338 AG proprietary blend, composition undisclosed Water water —

To prepare the formulation, 90% of the water was charged into a cooled reaction vessel. The MIPA 70 was added, stirring was commenced and continued with addition of the MEA.

Clopyralid Technical was added slowly, while maintaining the reaction temperature between 40 and 45° C. Upon completion of the Clopyralid Technical addition, the mixture was stirred for a further 30 mins to ensure complete dissolution.

The TERWET 1255 was added while stirring continued and thoroughly blended.

Rhodoline 5338 AG was premixed with the remaining water and then added to the formulation and blended thoroughly.

The clopyralid content was checked and adjusted with more water as required.

The resultant SL formulation was analysed. The analysis is in Table 3:

TABLE 3 Analysis Determination Method Specification Analysis Result Appearance, Visual Clear amber Clear amber liquid PASS Physical State & liquid Colour Odour Olfactory negligible negligible PASS pH - 1% v/v CIPAC MT 75.3 6.00-7.00 6.70 PASS dilution Density @ 20° C. Density Meter 1.249-1.263 g/mL 1.254 g/mL PASS Anton Paar DMA 48 Solution CIPAC MT 41 trace sediment nil sediment after PASS Stability 5.0 mL/100 ml after 30 mins 18 hrs Standard Water C Persistent foam CIPAC MT 47.2 max 60 mL Initial: 60 mL PASS Standard 1.0 mL/200 mL foam after After 10 sec: 33 mL Water C 1 min After 3 min: 0 mL After 12 min: 0 mL Brookfield SPI 50 rpm Limits not 58 cps @ 25° C. Viscosity SPI 50 rpm defined 112 cps @ 10° C. SPI 20 rpm 284 cps @ 0° C. Content Nominal 575-625 g/L 600 g/L N.T. Clopyralid

The formulation was suitable for packaging in a HDPE container with a screw cap closure.

The formulation was subjected to accelerated storage conditions in that HDPE container. It was determined to be stable to heat for 2 weeks at 54° C. and therefore is expected to be shelf stable for at least 2 years.

A 100 mL sample of the formulation which has been subjected to accelerated storage conditions as above was then moved to a centrifuge tube and subjected to seeded cold storage conditions for 7 days at 0° C. The absence of any separated material indicated that the formulation was cold storage stable.

The pH of the embodiment containing the MIPA and MEA salts is 6.70 (1% v/v dilution). The formulation has low persistent foam (0-5 mm after 60 seconds) and a density at 20° C. of 1.25 g/mL. The formulation is stable for all parameters according to the standard CIPAC accelerated testing regime of 14 days at 54° C.

In conclusion, the new clopyralid dual-salt formulation has a novel combination of clopyralid salts including a new salt (MIPA). This formulation enables a stable concentration of 600 g ae/L with a desirable viscosity profile of >50 to <300 cP at 0-25° C.

Formulations of other clopyralid dual salts, being the MIPA salt and another amine salt, may be made in the same general way, as will be apparent to one skilled in the art.

Example 2: Field Tests

Field trials were conducted to evaluate the efficacy of the SL clopyralid formulation of Example 1, identified as DS-11137.

Field Test 1: Forthside, Tasmania

At Forthside, Tasmania in 2018, a field trial was conducted to evaluate DS-11137 for bioequivalence with the commercially registered formulation “Victory Herbicide 300 SL”, containing 300 g clopyralid/L present as the triisopropanolamine salt, for control of volunteer faba beans (Vicia faba) and blue lupins (Lupinus angustifolius) in wheat cv. Beaufort.

Other products were also tested. The product details are in Table 4:

TABLE 4 Products Active Concentration Product ingredient of active name (ai) ingredient Formulation Supplier Victory clopyralid 300 g/L Soluble Adama 300 SL concentrate Australia Pty Limited MCPA LVE MCPA 570 g/L Emulsifiable Adama 570 EC concentrate Australia Pty Limited DS-11137 clopyralid 600 g/L Soluble concentrate

Treatments included:

-   -   Victory 300 SL and DS-11137 each applied solo at 45, 75 and 150         g ai/ha,     -   Victory 300 SL and DS-11137 each applied tank mixed with MCPA         LVE 570 EC at 400 g ai/ha,

Treatments are set out in Table 5:

TABLE 5 Treatments Rate Active Product ingredient Application No. Product (mL/ha) (g ai/ha) schedule 1 Untreated control Nil Nil N/A 2 Victory Herbicide 150 45 A single foliar 300 SL application made 3 Victory Herbicide 250 75 prior to wheat 300 SL reaching growth 4 Victory Herbicide 500 150 stage BBCH 30, 300 SL in a spray volume 5 Victory Herbicide 150 45 of 110 L/ha, 300 SL generating a MCPA LVE 700 400 coarse spray 570 EC droplet. 6 DS-11137 75 45 7 DS-11137 125 75 8 DS-11137 250 150 9 DS-11137 75 45 MCPA LVE 700 400 570 EC

Treatments were applied as a single foliar application when the wheat had one to two tillers (BBCH 21-22), in a spray volume of 110 L/ha generating a coarse spray quality. Weed control, crop safety and wheat vigour assessments were conducted at 14, 28 and 43 days after application (DAA). Weed counts were carried out at 43DAA. Volunteer faba bean control is shown in Table 6:

TABLE 6 Volunteer faba bean control Volunteer (% leaf area affected) Faba Bean Rate Chlorosis Epinasty Control No. Treatment (g ai/ha) 14 DAA 28 DAA 1 Untreated Nil 0 e 0 b control 2 Victory Herbicide 45 56 c 50 a 300 SL 3 Victory Herbicide 75 97 a 38 a 300 SL 4 Victory Herbicide 150 97 a 39 a 300 SL 5 Victory Herbicide 45 97 a 60 a 300 SL MCPA LVE 400 570 EC 6 DS-11137 45 95 a 40 a 7 DS-11137 75 97 a 45 a 8 DS-11137 150 98 a 59 a 9 DS-11137 45 98 a 51 a MCPA LVE 400 570 EC P-value 0.0001 0.0045 LSD (P ≤ 0.05) 14.8 23.8 DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, Duncan's New MRT)

DAA=Days after application

Means followed by the same letter are not significantly different (P=0.05, Duncan's New MRT)

Percent of volunteer faba bean leaf area affected by brownout is shown in Table 7:

TABLE 7 Volunteer Faba Bean Brownout Volunteer faba bean brownout Rate (% leaf area affected) No. Treatment (g ai/ha) 28 DAA 43 DAA 1 Untreated control Nil 0 b 0 c 2 Victory Herbicide 45 76 a 66 ab 300 SL 3 Victory Herbicide 75 62 a 100 a 300 SL 4 Victory Herbicide 150 75 a 83 ab 300 SL 5 Victory Herbicide 45 88 a 100 a 300 SL MCPA LVE 400 570 EC 6 DS-11137 45 65 a 100 a 7 DS-11137 75 70 a 88 ab 8 DS-11137 150 73 a 100 a 9 DS-11137 45 81 a 99 a MCPA LVE 400 570 EC P-value 0.0061 0.0001 LSD (P ≤ 0.05) 35.9 tA DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, Duncan's New MRT) tA = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Arcsine square root percent (x)

Blue Lupin control is shown in Table 8:

TABLE 8 Blue Lupin Control Blue lupin control (% leaf area affected) Rate Epinasty Brownout No Treatment (g ai/ha) 14 DAA 28 DAA 43 DAA 1 Untreated control Nil 0 d 0 d 0 e 2 Victory Herbicide 45 1 d 4 bcd 13 de 300 SL 3 Victory Herbicide 75 7 cd 13 ab 48 bcd 300 SL 4 Victory Herbicide 150 13 cd 2 cd 36 cde 300 SL 5 Victory Herbicide 45 83 a 24 ab 98 a 300 SL MCPA LVE 400 570 EC 6 DS-11137 45 6 cd 8 bc 30 cde 7 DS-11137 75 19 c 8 bcd 44 cd 8 DS-11137 150 9 cd 8 bc 73 abc 9 DS-11137 45 73 ab 10 bcd 64 abc MCPA LVE 400 570 EC P-value 0.0001 0.0007 0.0002 LSD (P ≤ 0.05) 12.6 tL tA DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, Duncan's New MRT) tL = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Log (x + 1) tA = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Arcsine square root percent (x)

Table 9 shows effectiveness of the treatments on each on volunteer faba bean and blue lupin at 43 days after application:

TABLE 9 Faba Bean and Blue Lupin Counts at 43 DAA Weed counts (Number per plot) Volunteer Rate faba beans Blue lupins No. Treatment (g ai/ha) 43 DAA 43 DAA 1 Untreated control Nil 27 a 22 a 2 Victory Herbicide 45 1 d 5 bc 300 SL 3 Victory Herbicide 75 0 d 2 cde 300 SL 4 Victory Herbicide 150 0 d 2 bcde 300 SL 5 Victory Herbicide 45 0 d 0 e 300 SL MCPA LVE 400 570 EC 6 DS-11137 45 0 d 9 ab 7 DS-11137 75 0 d 3 bcd 8 DS-11137 150 0 d 7 ab 9 DS-11137 45 0 d 2 cde MCPA LVE 400 570 EC P-value 0.0001 0.0001 LSD (P < 0.05) tL tL DAA = Days after application Note, treatment data with the same number but different letters of separation can result from statistics relying on transformed data Means followed by the same letter are not significantly different (P = 0.05, Duncan's New MRT) NSD = No significant difference due to a P-value > 0.05 tL = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Log (x + 1)

All treatments of Victory 300 SL and DS-11137 offered excellent control of volunteer faba beans and good control of blue lupin.

MCPA LVE 570 EC tank mixed with either Victory 300 SL or DS-11137 offered greater control of blue lupins than either product applied as standalone treatments.

All herbicide treatments mixed well with no issues at the time of spraying. All Victory 300 SL and DS-11137 treatments were safe to wheat cv. Beaufort under the conditions of this trial.

Field Test 2: Sassafras, Tasmania

At Sassafras, Tasmania, a field trial was conducted to evaluate DS-11137 for bioequivalence with Victory 300 SL for control of spear thistle (Cirsium vulgare) in a fallow situation.

The product details are in Table 10:

TABLE 10 Product Details Active Concentration ingredient of active Product name (ai) ingredient Formulation DS-11137 clopyralid 600 g/L Soluble concentrate Victory 300 SL clopyralid 300 g/L Soluble concentrate MCPA 500 AC MCPA 500 g/L Aqueous concentrate

Treatments included either DS-11137 and Victory 300 SL applied at 7.5, 15 or 21 g ai/ha in tank mixtures with MCPA 500 AC at 500 g ai/ha. (MCPA 500 AC is available through various suppliers.) Treatments were applied as a single foliar application to actively growing spear thistles at the 5 to 6 true leaf growth stage. Applications were made in a spray volume of 110 L/ha with air induction flat fan nozzles generating a coarse spray quality.

Table 11 shows the treatments:

TABLE 11 Treatments applied at Sassafras, Tasmania to evaluate DS-11137 in fallow Rate Active Product ingredient Application No. Product (mL/ha) (g ai/ha) schedule 1 Victory Herbicide 25 7.5 A single foliar 300 SL + application in a MCPA 500 AC 1000 500 spray volume of 2 Victory Herbicide 50 15 110 L/ha, 300 SL + generating a MCPA 500 AC 1000 500 coarse spray 3 Victory Herbicide 70 21 quality to 300 SL + actively growing MCPA 500 AC 1000 500 thistles at 4 DS-11137 + 12.5 7.5 BBCH 15-16. MCPA 500 AC 1000 500 5 DS-11137 + 25 15 MCPA 500 AC 1000 500 6 DS-11137 + 35 21 MCPA 500 AC 1000 500 7 Untreated control Nil Nil N/A

Spear thistle density was assessed prior to treatment application and again at 56 days after application (56DAA). Efficacy against spear thistle was assessed at 14, 28, 42 and 56DAA.

Table 12 details effect on spear thistle:

TABLE 12 Spear Thistle Curling and Chlorosis Thistle curling Thistle chlorosis Rate (% leaf area) (% leaf area) No. Treatment (g ai/ha) 14 DAA 28 DAA 1 Victory herbicide 7.5 15 15 a 300 SL MCPA 500 AC 500 2 Victory herbicide 15 23 18 a 300 SL MCPA 500 AC 500 3 Victory herbicide 21 19 18 a 300 SL MCPA 500 AC 500 4 DS-11137 7.5 19 14 a MCPA 500 AC 500 5 DS-11137 15 21 13 a MCPA 500 AC 500 6 DS-11137 21 20 20 a MCPA 500 AC 500 7 Untreated control Nil  0{circumflex over ( )} 0 b P-value     0.3691 0.0010 LSD (P ≤ 0.05) NSD 7.7 Factorial analysis Rate 7.5 + 500 g ai/ha  17 14 15 + 500 g ai/ha 22 15 21 + 500 g ai/ha 19 19 P-value     0.1481 0.2659 LSD (P ≤ 0.05) NSD NSD Formulation Victory herbicide 300 SL 19 17 MCPA 500 AC DS-11137 20 16 MCPA 500 AC P-value     0.5327 0.6108 LSD (P ≤ 0.05) NSD NSD DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, LSD) NSD = No significant difference due to a P-value > 0.05 {circumflex over ( )}Treatment 7 has been excluded from statistical analysis to correct for skewness

Table 13 shows necrosis as a percent of leaf area, while Table 14 shows spear thistle counts:

TABLE 13 Spear Thistle Necrosis Spear thistle necrosis Rate (% leaf area) No. Treatment (g ai/ha) 28 DAA 42 DAA 1 Victory herbicide 7.5 17 b 71 b 300 SL MCPA 500 AC 500 2 Victory herbicide 15 18 b 78 ab 300 SL MCPA 500 AC 500 3 Victory herbicide 21 18 b 84 a 300 SL MCPA 500 AC 500 4 DS-11137 7.5 13 c 73 b MCPA 500 AC 500 5 DS-11137 15 17 b 79 ab MCPA 500 AC 500 6 DS-11137 21 21 a 81 a MCPA 500 AC 500 7 Untreated control Nil 0 {circumflex over ( )} 0 {circumflex over ( )} P-value 0.0004 0.0218 LSD (P ≤ 0.05) 2.7 7.6 Factorial analysis Rate 7.5 g ai/ha  15 b 72 b 15 g ai/ha 17 a 78 a 21 g ai/ha 19 a 83 a P-value 0.0004 0.0028 LSD (P ≤ 0.05) 2 5 Formulation Victory herbicide 300 SL 17 78 MCPA 500 AC DS-11137 17 78 MCPA 500 AC P-value 0.5713 1.0000 LSD (P ≤ 0.05) NSD NSD DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, LSD) NSD = No significant difference due to a P-value > 0.05 {circumflex over ( )} Treatment 7 has been excluded from statistical analysis to correct for skewness

TABLE 14 Spear Thistle Counts Spear thistle counts Rate (number/m²) No. Treatment (g ai/ha) 0 DAA 56 DAA 1 Victory herbicide 7.5 — 0 300 SL MCPA 500 AC 500 2 Victory herbicide 15 — 0 300 SL MCPA 500 AC 500 3 Victory herbicide 21 — 0 300 SL MCPA 500 AC 500 4 DS-11137 7.5 — 0 MCPA 500 AC 500 5 DS-11137 15 — 0 MCPA 500 AC 500 6 DS-11137 21 — 0 MCPA 500 AC 500 7 Untreated control Nil 30 34{circumflex over ( )} P-value —    1.0000 LSD (P ≤ 0.05) — NSD Factorial analysis Rate 7.5 g ai/ha  — 0 15 g ai/ha — 0 21 g ai/ha — 0 P-value —    1.0000 LSD (P ≤ 0.05) — NSD Formulation Victory herbicide 300 SL — 0 MCPA 500 AC DS-11137 — 0 MCPA 500 AC P-value —    1.0000 LSD (P ≤ 0.05) — NSD DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, LSD) NSD = No significant difference due to a P-value > 0.05 {circumflex over ( )}Treatment 7 has been excluded from statistical analysis to correct for skewness

All herbicide treatments caused significant chlorosis to thistles at 28DAA.

All herbicide treatments caused equivalent leaf area necrosis to thistles at 28 and 42DAA.

All herbicide treatments significantly reduced thistle numbers compared to the untreated control.

DS-11137 was bioequivalent to Victory for the control of thistles at all assessments.

All treatments of Victory and DS-11137 gave complete control of spear thistle.

Field Test 3: Moriarty, Tasmania

At Moriarty, Tasmania, a field trial was conducted to evaluate DS-11137 the bioequivalence of Victory Herbicide 300 SL for control of slender thistle (Carduus tenuiflorus) and prickly sowthistle (Sonchus asper) and on pasture safety in a perennial grass pasture.

The products are detailed in Table 15:

TABLE 15 Products Active Concentration ingredient of active Product name (ai) ingredient Formulation DS-11137 clopyralid 600 g/L Soluble concentrate Victory Herbicide Clopyralid present 300 g/L Soluble 300 SL as the concentrate triisopropanolamine salt MCPA 500 SL MCPA present as the 500 g/L Soluble dimethylamine salt concentrate

As shown in Table 16, treatments included either DS-11137 or Victory Herbicide applied at 15, 21 or 42 g ai/ha in tank mixtures with MCPA 500 SL at 500 g ai/ha. Treatments were applied as a single foliar spray to actively growing thistles at the 4-leaf to large rosette growth stage. Applications were made in a spray volume of 100 L/ha with air induction flat fan nozzles generating a coarse spray quality.

TABLE 16 Treatments Rate Active Product ingredient Application No. Product (mL/ha) (g ai/ha) schedule 1 Untreated control Nil Nil N/A 2 Victory Herbicide 50 + 15 Single foliar 300 SL + application with MCPA 500 SL 1000 500 Lechler IDK 120-01 3 Victory Herbicide 70 + 21 air induction flat fan 300 SL + nozzles in a spray MCPA 500 SL 1000 500 volume of 100 L/ha 4 Victory Herbicide 140 + 42 300 SL + MCPA 500 SL 1000 500 5 DS-11137 + 25 + 15 MCPA 500 SL 1000 500 6 DS-11137 + 35 + 21 MCPA 500 SL 1000 500 7 DS-11137 + 70 + 42 MCPA 500 SL 1000 500

Slender thistle density was assessed prior to treatment application and again at 42 days after application (42DAA), when plant numbers were also assessed. Efficacy against slender thistle was assessed at 14, 27 and 42 days after application (DAA). The results at 42DAA are in Table 17:

TABLE 17 Slender thistle counts at 0 DAA and 42 DAA, and prickly sowthistle count at 42 DAA Number of plants (plants/plot) Slender Slender Sow Rate thistle thistle thistle No Treatment (g ai/ha) 0 DAA 42 DAA 42 DAA 1 Untreated control Nil 11 10 a 3 a 2 Victory Herbicide 15 13 0 b 1 b 300 SL + MCPA 500 SL 500 3 Victory Herbicide 21 19 0 b 1 b 300 SL + MCPA 500 SL 500 4 Victory Herbicide 42 12 0 b 0 b 300 SL + MCPA 500 SL 500 5 DS-11137 + 15 13 0 b 0 b MCPA 500 SL 500 6 DS-11137 + 21 14 0 b 0 b MCPA 500 SL 500 7 DS-11137 + 42 14 0 b 0 b MCPA 500 SL 500 P-value 0.9819 0.0001 0.0004 LSD (P ≤ 0.05) NSD (tL*) tL tA Factorial analysis Rate 15 + 500 g ai/ha 13 0 0 21 + 500 g ai/ha 17 0 0 42 + 500 g ai/ha 13 0 0 P-value 0.6232 0.7939 0.6346 LSD (P ≤ 0.05) NSD NSD NSD Formulation Victory Herbicide 15 0 0 300 SL + MCPA 500 SL DS-11137 + 14 0 0 MCPA 500 SL P-value 0.7151 0.3483 0.1347 LSD (P ≤ 0.05) NSD NSD NSD DAA = Days after application Means followed by the same letter are not significantly different (P = 0.05, Duncan's New MRT) NSD = No significant difference due to a P-value > 0.05 tL* = P-value and LSD from data transformed using y = Log (x + 1) tL = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Log (x + 1) tA = Original plot means are presented with analysis of variance and letters of separation from data transformed using y = Arcsine square root percent (x)

All herbicide treatments completely controlled slender thistle at 42DAA and had significant control of prickly sowthistle.

DS-11137 and Victory Herbicide were bioequivalent for effect on slender thistle and prickly sowthistle. Each demonstrated a greater effect on slender thistle at 14DAA when applied at higher rates, though by 27DAA were equivalent at all applied rates.

DS-11137 and Victory Herbicide, at rates of 15 to 42 g ai/ha, each in tank mixtures with MCPA, were safe to the perennial grass pasture under the conditions of this trial with no visible signs of phytotoxicity.

DS-11137 and Victory Herbicide both mixed readily with MCPA with no compatibility issues during application.

Field Test 4: Padthaway, South Australia

At Padthaway in South Australia, a field trial was conducted to evaluate crop safety and efficacy of DS-11137 compared to the registered formulation “Genfarm Clopyralid 600”, when applied to canola cv. 45Y93CL, the weed being volunteer lucerne (Medicago sativa). (Genfarm Clopyralid 600 is supplied by Nutrien Ag Solutions Limited.)

The canola crop was sown in a moist clay loam soil with a knife point press wheel system at a rate of 3.0 kg/ha to a depth of 1.0 cm. The previous crop had been lucerne.

At 65 days after sowing, when the crop stage had reached BBCH scale 16, treatments 2 to 5 in Table 18 below were applied:

TABLE 18 Treatments Rate Active Product ingredient No. Product (mL or g/ha) (g ai/ha) 1 Untreated control Nil Nil 2 Genfarm Clopyralid 600 150 90 3 Genfarm Clopyralid 600 300 180 4 DS-11137 150 90 5 DS-11137 300 180

Each of Genfarm Clopyralid 600 and DS-11137 is a soluble concentrate with active ingredient Clopyralid at a formulation concentration of 600 g/L. In Genfarm Clopyralid, clopyralid is present as the dimethylamine salt.

Crop vigour and crop phytotoxicity were assessed at 7 days after application (DAA) and again at 14 DAA. Lucerne control was assessed at 7 DAA.

Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.

Crop phytotoxicity was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.

Weed control was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no control and 100%=complete control/weed death.

The results are set out in Tables 19 to 21:

TABLE 19 Results - Crop Vigour of Canola cv 45Y93CL Rate Active Crop Vigour (mean % relative ingredient to untreated control) No. Product (g ai/ha) 7 DAA 14 DAA 1 Untreated Nil 100 100 control 2 Genfarm 90 100 99 Clopyralid 600 3 Genfarm 180 100 100 Clopyralid 600 4 DS-11137 90 99.5 99.5 5 DS-11137 180 100 98.8

There was no significant difference between the results for crop vigour.

TABLE 20 Results - Crop Phytotoxicity of Canola cv 45Y93CL Rate Active Crop Phytotoxicity ingredient (mean %) No. Product (g ai/ha) 7 DAA 14 DAA 1 Untreated Nil 0 0 control 2 Genfarm 90 0 0 Clopyralid 600 3 Genfarm 180 0 0 Clopyralid 600 4 DS-11137 90 0 0 5 DS-11137 180 0 0

There was no significant difference between the results for crop phytotoxicity.

TABLE 21 Results - Lucerne Control Rate Active Lucerne Control (mean % relative ingredient to untreated control) No. Product (g ai/ha) 7 DAA 1 Untreated Nil 0 b control 2 Genfarm 90 27.5 a Clopyralid 600 3 Genfarm 180 27.5 a Clopyralid 600 4 DS-11137 90 28.8 a 5 DS-11137 180 28.8 a

Means followed by the same letter do not significantly differ.

As shown in Tables 19 to 21, none of treatments 2 to 5 recorded any significant reduction in crop vigour relative to the untreated control. No symptoms of crop phytotoxicity were evident at 7 or 14 DAA for any of the herbicide treatments. A very low population of lucerne was present across the trial at the time of treatment application. Symptoms of suppression were evident across all herbicide treatments at 7 DAA, consisting of plant wilting and reduced vigour. Although this was mild, both formulations of clopyralid were statistically equivalent, with no difference between application rates.

Field Test 5: Auburn, South Australia

At Auburn in South Australia, a field trial was conducted to evaluate crop safety of DS-11137 compared to the registered formulation “Genfarm Clopyralid 600”, when applied to barley cv. Compass. The previous crop had been wheat.

The barley crop was sown in a moist clay loam soil with a knife point press wheel system at a rate of 90 kg/ha to a depth of 2.5 cm.

At 68 days after sowing, when the crop stage had reached BBCH scale 22, treatments 2 to 5 in Table 22 below were applied:

TABLE 22 Treatments Rate Active Product ingredient No. Product (mL or g/ha) (g ai/ha) 1 Untreated control Nil Nil 2 Genfarm 250 150 Clopyralid 600 3 Genfarm 500 300 Clopyralid 600 4 DS-11137 250 150 5 DS-11137 500 300

Each of Genfarm Clopyralid 600 and DS-11137 is a soluble concentrate with active ingredient Clopyralid at a formulation concentration of 600 g/L. In Genfarm Clopyralid, clopyralid is present as the dimethylamine salt.

Crop vigour and crop phytotoxicity were assessed at 7 days after application (DAA) and again at 15 DAA.

Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.

Crop phytotoxicity (such as chlorosis, necrosis) was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.

The results are set out in Tables 23 and 24 below.

None of treatments 2 to 5 recorded any significant reduction in crop vigour relative to the untreated control. No symptoms of crop phytotoxicity were evident at 7 or 14 DAA for any of the herbicide treatments. Both formulations of clopyralid were statistically equivalent, with no difference between application rates.

TABLE 23 Results - Crop Vigour of Barley cv. Compass Rate Active Crop Vigour (mean % relative ingredient to untreated control) No. Product (g ai/ha) 7 DAA 14 DAA 1 Untreated Nil 100 100 control 2 Genfarm 150 100 100 Clopyralid 600 3 Genfarm 300 100 99.5 Clopyralid 600 4 DS-11137 150 100 99.5 5 DS-11137 300 100 100

There was no significant difference between the results for crop vigour.

TABLE 24 Results - Crop Phytotoxicity of Barley cv. Compass Rate Active ingredient Crop Phytotoxicity (mean %) No. Product (g ai/ha) 7 DAA 14 DAA 1 Untreated Nil 0 0 control 2 Genfarm 150 0 0 Clopyralid 600 3 Genfarm 300 0 0 Clopyralid 600 4 DS-11137 150 0 0 5 DS-11137 300 0 0

There was no significant difference between the results for crop phytotoxicity.

Field Test 6: York, Western Australia

At York in Western Australia, a field trial was conducted to evaluate DS-11137 for pre-emergence control of volunteer pulses and other broadleaf weeds in wheat (Triticum), while assessing crop safety and yield effects. The efficacy of DS-11137 was compared with that of standard registered herbicides.

The wheat crop (cv. Sceptre) was sown in an untilled seed bed, the soil being grey sand, using a knife point press wheel system at a rate of 70 kg/ha to a depth of 1-1.5 cm. The previous crop had been barley.

Pre-emergently, the following herbicides were applied: Countdown at 2.5 L/ha, Trilogy at 1.6 L/ha and Roundup Ultra Max at 2 L/ha. Countdown and Trilogy are supplied by Adam Australia Pty Limited; Roundup Ultra Max is supplied by Bayer CropScience Pty Limited.

Treatments in the trial, set out in Table 25, were applied pre-planting and incorporated by sowing:

TABLE 25 Treatments Rate Active Product ingredient No. Product (mL or g/ha) (g ai/ha) Supplier 1 Untreated Nil Nil control 2 Callisto 480 g/L 100 ml/ha 48 Syngenta Australia Mesotrione SC Pty Limited 3 Gallery 750 g/kg 140 g/ha 105 Dow Agroscience Isoxaben WG Australia Limited 4 DS-11137600 g/L 75 ml/ha 45

To assess crop safety, the number of wheat plants per square metre were counted at 31 days after sowing (DAS). The results are in Table 26 below. Crop phytotoxicity was assessed at 31 DAS and again at 55 DAS: see Table 27. Crop vigour assessments for the same period are shown in Table 28.

TABLE 26 Results - Crop Safety: Emergence counts (plants/m²) at 31 DAS Application 31 DAS No. Product Rate (plants/m²) 1 Untreated Nil 185 control 2 Callisto 480 g/L 100 ml/ha 179 Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 188 Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 183

There were no significant differences in crop emergence in response to the treatments.

TABLE 27 Results - Crop Phytotoxicity (%) at 31 DAS and 55 DAS Application Crop Phytotoxicity No. Product Rate 31 DAS 55 DAS 1 Untreated Nil 0 0 control 2 Callisto 480 g/L 100 ml/ha 0 0 Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 0 0 Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 0 0

There were no phytotoxic effects.

TABLE 28 Results - Crop Vigour (%) at 31 DAS and 55 DAS Application Crop Phytotoxicity No. Product Rate 31 DAS 55 DAS 1 Untreated Nil 100 100 control 2 Callisto 480 g/L 100 ml/ha 100 100 Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 100 100 Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 100 100

There was no reduced vigour observed in response to any treatment.

The primary target species in the trial were volunteer pulses including chickpeas (Cicer arietinum), field peas (Pisum sativum) and lupins (Lupinis) in wheat. Tables 29, 30 and 31 show percent control of each of these, assessed at 55 DAS and 79 DAS.

TABLE 29 Chickpea Control (%) at 55 DAS and 79 DAS Application Chickpea Control No. Product Rate 55 DAS 79 DAS 1 Untreated Nil 0 f 0 g control 2 Callisto 480 g/L 100 ml/ha 99 ab 92 bcd Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 65 e 65 f Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 100 a 100 a

Means followed by the same letter are not significantly different.

Table 29 shows that DS-11137 demonstrated strong control over chickpeas and performed significantly better than Gallery.

TABLE 30 Field Pea Control (%) at 55 DAS and 79 DAS Application Chickpea Control No. Product Rate 55 DAS 79 DAS 1 Untreated Nil 0 d 0 f control 2 Callisto 480 g/L 100 ml/ha 100 a 100 a Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 27 c 19 e Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 97 a 99 a

Means followed by the same letter are not significantly different.

Table 30 shows that DS-11137 demonstrated significant control over field peas, once again performing significantly better than Gallery.

TABLE 31 Lupin Control (%) at 55 DAS and 79 DAS Application Chickpea Control No. Product Rate 55 DAA 79 DAA 1 Untreated Nil 0 d 0 h control 2 Callisto 480 g/L 100 ml/ha 97 a 33 def Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 78 c 23 efg Isoxaben WG 4 DS-11137 600 g/L 75 ml/ha 94 ab 35 def

Means followed by the same letter are not significantly different.

Table 31 shows that DS-11137 demonstrated comparable control over lupins, compared with Callisto and superior performance compared to Gallery. All treatments decreased in efficacy over lupins from 55 DAS to 79 DAS.

Field Test 7: Roseworthy, South Australia

A field trial was conducted to evaluate DS-11137 for pre-emergence control of volunteer pulses: lentil (Lens culinaris), field peas (Pisum sativum arvense) and chickpea (Cicer arietinum) in wheat cv. Sceptre.

These treatments were compared to registered herbicide Gallery and Adama Mesoflex (a suspension concentrate formulation of 480 g/L of Mesotrione, available from Adama Australia Pty Limited). The treatments, which are set out in Table 32, were applied pre-planting and incorporated by sowing (IBS).

TABLE 32 Treatments Rate Active Product ingredient No. Product (mL or g/ha) (g ai/ha) Supplier 1 Untreated Nil Nil control 2 ADAMA 100 mL 48 Adama Australia Mesoflex 480 g/L Pty Limited Mesotrione SC 3 Gallery 750 g/kg 140 g/ha 105 Dow Agroscience Isoxaben WG Australia Limited 4 DS-11137600 g/L 75 ml/ha 45

The wheat crop (cv. Sceptre) was sown in a moist clay loam soil with a knife point press wheel system at a rate of 100 kg/ha to a depth of 2 to 3 cm.

At 25 days after sowing, when the crop stage had reached BBCH scale 12, crop emergence was noted. At 26 days after sowing, crop vigour and phytotoxicity were assessed, as well as weed control. At 56 days after sowing, the crop stage had reached BBCH scale 22; crop vigour and phytotoxicity were assessed, as well as weed control.

Crop emergence was assessed by counting 6 times per plot the number of plants along 50 cm of row and recording the result as the number of plants/m row.

Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.

Crop phytotoxicity was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.

Weed control was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no control and 100%=complete control/weed death, relative to the untreated control.

The results are set out in Tables 33 to 38:

TABLE 33 Results - Crop Safety: Emergence counts (plants/m²) at 25 DAS Application Emergence Rate 25 DAS No. Product (g ai/ha) (mean no./row) 1 Untreated Nil 51.1 control 2 Adama 48 50.0 Mesoflex 3 Gallery 105 49.8 4 DS-11137 45 49.8

There were no significant differences in crop emergence in response to the treatments.

TABLE 34 Results - Crop Vigour (%) at 26 DAS and 56 DAS Application Rate Crop Phytotoxicity No. Product (g ai/ha) 26 DAS 56 DAS 1 Untreated Nil 100 100 control 2 Adama 48 99.8 99.5 a Mesoflex 3 Gallery 105 99.8 98.5 a 4 DS-11137 45 100 98.8 a

Means followed by the same letter are not significantly different.

There was no reduced vigour observed in response to any treatment. Crop vigour for DS11137 at 45 g ai/ha was equivalent to the untreated control, Mesoflex and registered herbicide Gallery.

TABLE 35 Results - Crop Phytotoxicity (%) at 26 DAS and 56 DAS Application Rate Crop Phytotoxicity No. Product (g ai/ha) 26 DAS 56 DAS 1 Untreated Nil 0.0 0.0 f control 2 Adama 48 0.0 0.0 f Mesoflex 3 Gallery 105 0.0 0.3 ef 4 DS-11137 45 0.0 0.8 ef

Means followed by the same letter are not significantly different.

There were no symptoms of crop phytotoxicity at 26 DAS. DS11137, Gallery and Mesoflex were not associated with any significant crop phytotoxicity compared to the untreated control at 56DAS.

TABLE 36 Volunteer Lentil (Lens culinaris) control (%) at 26 DAS and 56 DAS Lentil control (means % Application relative to untreated Rate control) No. Product (g ai/ha) 26 DAS 56 DAS 1 Untreated Nil 0.0 d 0.0 g control 2 Adama 48 87.3 a 86.3 d Mesoflex 3 Gallery 105 57.5 b 71.3 e 4 DS-11137 45 98.3 a 99.3 a

Means followed by the same letter are not significantly different.

DS11137 recorded almost complete control of volunteer lentil at both 26 and 56 DAS and was significantly more effective than both Gallery and Mesoflex.

TABLE 37 Volunteer Field Peas (Pisum sativum arvense) control (%) at 26 and 56 DAS Application Field Pea control (means % Rate relative to untreated control) No. Product (g ai/ha) 26 DAS 56 DAS 1 Untreated Nil 0.0 f 0.0 f control 2 Adama 48 95.8 abc 80.0 c Mesoflex 3 Gallery 105 58.8 d 45.0 d 4 DS-11137 45 96.5 abc 94.0 a

Means followed by the same letter are not significantly different.

For field peas, DS11137 provided a high level of control that was statistically equivalent to the other best performing treatments and significantly higher than Gallery and Mesoflex at 56 DAS.

TABLE 38 Volunteer Chickpea (Cicer arietum) control (%) at 56 DAS Application Chickpea control (means % Rate relative to untreated control) No. Product (g ai/ha) 56 DAS 1 Untreated Nil 0.0 f control 2 Adama 48 52.5 de Mesoflex 3 Gallery 105 32.5 e 4 DS-11137 45 99.8 a

Means followed by the same letter are not significantly different.

D511137 recorded almost complete control of chickpea at 56 DAS and was significantly more effective than Mesoflex and Gallery.

The above results show that DS11137, applied IBS at 45 g ai/ha, did not record a significant reduction in crop vigour compared to the untreated control or any significant crop phytotoxic symptoms, but recorded a high level of control of volunteer lentil (99%), field pea (94%) and chickpea (100%).

It will be appreciated from the data in the above tables that the efficacy of the formulations of the invention is at least comparable to that of prior art formulations and in many cases superior to prior art formulations. The formulations of the invention, being more concentrated, are more efficient.

In addition, an increase in concentration from 300 g ae/L to 600 g ae/L of clopyralid represents a 50% reduction in the volume of material to be formulated, transported, stored and applied by the end user. 

1. A clopyralid formulation comprising clopyralid at a concentration of at least 600 g ae/L, clopyralid being present in the form of at least two amine salts, one of which is the monoisopropylamine salt.
 2. The formulation of claim 1, wherein clopyralid is present in the form of two amine salts, the second amine salt being the monoethanolamine salt.
 3. The formulation of claim 1, wherein the formulation is in the form of a soluble liquid.
 4. The formulation of claim 1, wherein the formulation further comprises at least one other herbicide in a tank mix.
 5. The formulation of claim 4, wherein the other herbicide is MCPA (2-methyl-4-chlorophenoxyacetic acid.)
 6. A method of controlling one or more weeds in a crop, the method comprising applying the formulation of claim 1 to the crop.
 7. The method of claim 6, wherein the crop is selected from the group consisting of wheat, canola and barley.
 8. The method of claim 7, wherein the or each weed is selected from the group consisting of faba beans (Vicia faba), blue lupins (Lupinus angustifolius), volunteer lucerne (Medicago sativa), chickpea (Cicer arietinum), field peas (Pisum sativum), lupins (Lupinis) and lentil (Lens culinaris).
 9. A method of controlling one or more weeds in a fallow area or pasture crop, the method comprising applying the formulation of claim 1 to the fallow area or pasture crop.
 10. The method of claim 9, wherein the weed is selected from the group consisting of spear thistle (Cirsium vulgare), slender thistle (Carduus tenuiflorus) and prickly sowthistle (Sinchus asper). 